Blue luminescent graphene quantum dot conjugated cysteamine functionalized-gold nanoparticles (GQD-AuNPs) for sensing hazardous dye Erythrosine B.

Erythrosine B (ErB) is a xanthenes approved dye that widely used in various fields such as foods, drugs and cosmetics. This work intended to analyze the interaction of this dye on synthesized graphene quantum dot conjugated cysteamine functionalized gold nanoparticles. Pyrolysis of citric acid was applied to graphene quantum dots (GQDs) synthesis. These are zero dimensional materials promising considerable applications because of their extraordinary physicochemical properties. In this work, to improve its applications conjugates of GQDs and gold nanoparticles (GQD-AuNPs) are synthesized and characterized with FESEM, TEM, EDX and FTIR techniques. Interaction of ErB with synthesized conjugates was investigated using fluorescence technique and the results demonstrate that ErB can quench fluorescence of GQD-AuNPs conjugates, considerably. At last, we used of this good interaction for construction sensor for detection of ErB in the concentration range of 1.2 nM to 50 nM and the obtained LOD was 0.03 nM (S/N = 3) with correlation coefficient of (99%).